Five Questions to Ask Before Accepting an IBS Diagnosis

Irritable bowel syndrome is real, common and genuinely disabling for some people. It affects around one in ten adults, and there is nothing second-rate about the diagnosis.

But it is also, in practice, sometimes used as a label for abdominal symptoms where nothing much was investigated. And because the symptoms of IBS overlap almost exactly with several conditions that have specific treatments, that matters.

Here are five things worth confirming before you accept the label and stop looking.

1. Have I been screened for coeliac disease?

This is the most important question on the list, and the omission is common enough to be worth putting first.

Coeliac disease affects roughly 1 in 100 people in the UK, and a large proportion are undiagnosed. Its symptoms — bloating, loose stools, abdominal pain, fatigue — are effectively indistinguishable from IBS. UK guidance recommends testing for coeliac disease in anyone presenting with IBS-type symptoms. It is a blood test.

The critical detail, and the reason many tests come back falsely negative: you must be eating gluten regularly for the test to work. Guidance is more than one gluten-containing meal a day for at least six weeks beforehand. If you cut out gluten because it seemed to help — which is exactly what someone with undiagnosed coeliac disease would do — the test will very likely be negative.

A negative test in someone already gluten-free means nothing at all, and is regularly treated as a definitive exclusion.

2. Has my iron been checked — including ferritin?

A full blood count alone is not enough. Ferritin can be low while haemoglobin is still normal, and that is a meaningful finding.

IBS does not cause iron deficiency. If your iron is low, something else is going on — coeliac disease, inflammatory bowel disease, or blood loss from the gut. This is one of the clearest signals that the diagnosis needs revisiting.

Inflammatory markers — CRP and ESR — are also worth having. Again, IBS does not raise them.

3. Have I had a faecal calprotectin test?

This is a stool test that measures inflammation in the bowel, and it is the single most useful test for distinguishing IBS from inflammatory bowel disease — Crohn's disease and ulcerative colitis.

It is non-invasive, inexpensive and highly effective at answering exactly the question that matters. It is also under-used, particularly in younger adults where IBD is most likely to begin.

A normal calprotectin is strongly reassuring. A raised one warrants gastroenterology referral.

4. Could this be bile acid malabsorption?

This one is barely known outside gastroenterology, and it is a genuine gap.

Bile acid malabsorption causes watery, urgent diarrhoea — often first thing in the morning, often with little warning. It is estimated to account for a substantial proportion of people diagnosed with diarrhoea-predominant IBS, and it is frequently missed for years.

What makes it worth chasing: it responds well to a specific treatment, a bile acid sequestrant such as colestyramine or colesevelam. People who have managed symptoms for a decade sometimes improve within days.

It is particularly likely if your symptoms began after gallbladder removal, after gut surgery, or after a course of radiotherapy — but it also occurs without any of those.

Diagnosis is by a SeHCAT scan, or sometimes by a trial of treatment.

5. Is my age or symptom pattern actually typical?

IBS usually starts before the age of 50, and typically in the twenties or thirties.

New IBS-type symptoms beginning after 50 should be investigated rather than labelled. That is not a subtle guideline point — it is explicit, and it exists because bowel and ovarian cancers present exactly this way.

Similarly, IBS does not typically cause:

• Symptoms that wake you at night
• Weight loss
• Bleeding
• Fever
• Symptoms that are relentlessly progressive rather than fluctuating

IBS characteristically waxes and wanes, often with pain relieved by opening your bowels, and often flaring with stress. A steadily worsening picture is not the usual pattern.

Other things worth thinking about

Medication. Metformin, some antidepressants, magnesium supplements, iron and long-term omeprazole all cause bowel symptoms. A medication review is a cheap first step.

Endometriosis. In women with pelvic pain and bowel symptoms that change with the menstrual cycle, endometriosis is a serious consideration. Average time to diagnosis in the UK is measured in years, and an IBS label is one of the commonest detours along the way.

Thyroid function. An overactive thyroid causes loose stools; an underactive one causes constipation. Both are easily tested.

Persistent bloating. Bloating on most days for three weeks or more — particularly with feeling full quickly or pelvic pain, and particularly over 50 — warrants assessment for ovarian cancer. See bloating.

If it is IBS — and it often is

None of this is an argument against the diagnosis. IBS is the correct answer for a great many people, and once the alternatives are excluded there is a lot that can be done.

The low-FODMAP diet has good evidence, though it is best done with a dietitian and is not intended to be permanent. Soluble fibre helps some people. Antispasmodics, peppermint oil, and low-dose amitriptyline all have a place. Gut-directed hypnotherapy and CBT have a stronger evidence base than most people expect — this is about the gut-brain axis, not about the symptoms being imaginary.

What makes the difference is confidence in the diagnosis. It is very hard to commit to managing a condition while quietly wondering whether something was missed. Getting the exclusions done properly is what allows the treatment to work.

The practical version

Ask for, or arrange: coeliac screening (while still eating gluten), full blood count, ferritin, CRP, thyroid function and faecal calprotectin.

That set answers most of the questions above, and it is not an unreasonable request.

A consultation can review your history, arrange the full screen, and refer where the results warrant it.